Palmoplantar Plaque Psoriasis associated with Diabetes, Hypertension, Obesity, and Metabolic Syndrome- IDOJ Study

Psoriasis is a T cell‑mediated skin disease that affects about 0.44–2.8% of the Indian population. Palmoplantar psoriasis is a regional variant of psoriasis accounting for 10–12% of all psoriasis cases and is characterized by well‑defined erythematous, scaly plaques over palms and soles, and painful fissures over thick plaques with or without pustules. It is usually resistant to topical therapy and systemic therapy is required for management. Chronic plaque psoriasis is associated with various comorbidities such as psoriatic arthritis, obesity, diabetes mellitus, hypertension, dyslipidemia, metabolic syndrome, inflammatory bowel disease, cardiovascular disease, non‑alcoholic fatty liver disease, and depression. However, there is a paucity of literature on the association of various comorbidities with palmoplantar psoriasis. Most comorbidities in chronic plaque psoriasis have a dose– effect relationship and patients with severe psoriasis have a higher risk of development of comorbidities. Palmoplantar psoriasis typically involves less than 5% of body surface area. Recently a study investigating the association of comorbidities such as obesity, diabetes mellitus, hypertension, and metabolic syndrome with palmoplantar psoriasis was published in the Indian Dermatology Online Journal.

Methodology

This was a hospital‑based case–control study at a tertiary‑care dermatology center in western Maharashtra from January 2020 to June 2021. Treatment naïve palmoplantar plaque psoriasis patients of age > 18 years were included in the study. Patients with chronic plaque psoriasis, palmoplantar pustulosis, chronic hand eczema, and patients with a history of drug intake, such as oral contraceptive pills, systemic corticosteroids, and retinoids, and pregnant and lactating women were excluded from the study. The controls included patients reporting to the dermatology department with unrelated and common complaints such as melasma and dermatophytosis. Relevant data included age, gender, weight, height, body mass index, waist circumference, blood pressure, history of smoking and alcohol intake, age of onset, and duration of palmoplantar psoriasis. The severity assessment was done using a modified score for PPP (mPPPASI). History of diabetes mellitus and hypertension was recorded.

Diagnosis of comorbidities

• Obesity was diagnosed based on Indian consensus group guidelines that classify a BMI ≥25 kg/m² as obese
• Diabetes mellitus was diagnosed based on the American Diabetes Association criteria—fasting blood glucose ≥126 mg/dL or 2 hours post‑prandial glucose ≥200 mg/dL or patient already on treatment for diabetes.
• Hypertension was diagnosed based on the International Society of Hypertension—Global hypertension practice guidelines: systolic blood pressure ≥140 mmHg and/ or diastolic blood pressure ≥90 mmHg or patient on treatment for hypertension.
• Metabolic syndrome was diagnosed by the presence of three or more of the five criteria of the National Cholesterol Education Programme′s Adult Panel III (ATP III) modified for South Asians: waist circumference >90 cm in men or >80 cm in women; triglycerides >150 mg/dl or on treatment; high‑density lipoprotein (HDL) cholesterol <40 mg/dl in men or <50 mg/dl in women; blood pressure >130/85 mmHg or treatment; fasting plasma glucose >100mg/dl or type 2 diabetes mellitus or treatment.
• Psoriatic arthritis was diagnosed on the basis of classification criteria for psoriatic arthritis.

Statistical Analysis

The categorical variables are reported as frequency and percentage and the continuous variable as mean and standard deviation. The Chi‑square test was used to compare the categorical variables and the independent t‑test to compare the quantitative variables among the two groups. Odd's ratio with a 95% confidence interval (CI) was calculated for the presence of comorbidities in patients. All statistical tests were two‑sided and a p value of less than 0.05 was considered statistically significant. SPSS version 20 was used for all statistical analyses.

Results

The study included 100 cases and 100 age‑ and sex‑matched controls. The mean age among cases and controls was 45.4 ± 11.1 and 43.9 ± 10.3 years, respectively (P: 0.31). The gender ratio among cases and controls was 1.56 (61M: 39 F) and 1.94 (66M: 34F), respectively.

Alcohol consumption and smoking were more common among cases as compared to controls. The difference was statistically significant for alcohol consumption (P: 0.09). Comorbidities including metabolic syndrome (MetS), obesity, diabetes mellitus, and hypertension were more common among cases as compared to the controls. MetS was seen in 53 (53%) cases as compared to 23 (23%) controls (P: 0.001). Diabetes mellitus was present in 50 (50%) cases as compared to 17 (17%) controls (P: 0.001). Hypertension was noted in 41 (41%) cases as compared to 19 (19%) controls (P: 0.001). Obesity was seen in 54 (54%) cases as compared to 25 (25%) controls (P: 0.001).

• The mean systolic blood pressure among cases and controls was 129.30 (± 11.65) and 119.90 (± 10.04) mmHg, respectively (P: 0.001).
• The mean diastolic blood pressure among cases and controls was 81.78 (± 6.79) and 77.36 (± 5.92) mmHg, respectively (P: 0.001).
• The total mean BMI was 26.37 (± 3.99) and 25.17 (± 1.65) kg/m² among cases and controls, respectively (P: 0.006).
• The total mean waist circumference was 94.5 (± 10.1) and 87.8 (± 8.31) cm among cases and controls, respectively (P: 0.001).
• The fasting sugar levels among cases and controls were 107.8 (± 25.5) and 92.6 (± 27) mg/dL, respectively (P: 0.001).
• The postprandial sugar levels were 154.8 (± 65.1) and 120.4 (± 34.1) mg/dL among cases and controls, respectively (P: 0.001).
• The odds of diabetes, MetS, hypertension, and obesity in patients with palmoplantar psoriasis were 4.8 (95% CI 2.5–9.3), 3.7 (95% CI 2–6.9), 3.1 (95% CI 1.6–6), and 3.5 (95% CI 1.9–6.4), respectively.
• The statistical analysis for psoriatic arthritis was not performed as only one case had psoriatic arthritis in the patient group.
• The mean mPPPASI was 12.3 ± 9.5, and it did not show any statistically significant correlation to any of the parameters under investigation on bivariate analysis.

Discussion

Palmoplantar psoriasis, despite limited body surface area involvement, it causes a severe impact on quality of life due to the involvement of palms and soles, thereby hampering occupational as well as leisure‑time activities. Involvement of palms also results in social embarrassment as handshake and other social gestures make patients increasingly conscious of their illness. Chronic plaque psoriasis is known to be associated with numerous comorbidities but such data about palmoplantar psoriasis is scarce.

The expansion of Th1 and Th17 cells in psoriasis results in elevated levels of Th1 and Th17 cytokines in the skin and blood. It is postulated that these inflammatory mediators affect insulin signaling, adipogenesis, lipid metabolism, and immune cell trafficking that are responsible for central obesity, hypertension, insulin resistance, and accelerated atherosclerosis. The risk of these comorbidities, especially MetS and cardiovascular disease, is higher in patients with severe psoriasis.

To conclude palmoplantar psoriasis is associated with a high risk of obesity, diabetes mellitus, hypertension and MetS so all palmoplantar psoriasis patients irrespective of severity of the disease must also be screened for metabolic comorbidities.

Source- Rathod A, Neema S, Radhakrishnan S, Vendhan S, Tripathy DM, Vasudevan B. Palmoplantar plaque psoriasis is associated with diabetes, hypertension, obesity and metabolic syndrome—A case–control study. Indian Dermatol Online J 2022;13:606-10.